growing cress experiment year 3

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Grow your own yummy cress by making a Mr Cress head

Grow some veg with a smile by creating this fun Mr cress head

Growing Tips

What you'll need:.

• The foot end of a pair of tights
• Cress seeds
• Rubber bands
• Wiggly eyes, pipe cleaners, felt, natural objects e.g. acorns and seeds

Growing tips

• Place the foot end of a pair of tights inside the cup and overlap the top.
• Put about two teaspoons of cress seeds inside the tights. Almost fill the tights with compost.
• Remove the tights from the cup and tie the end. Turn it over so the cress seeds are at the top.
• Pull out some of the tights with compost inside it to make the nose. Use a rubber band to hold it in place.
• Decorate the rest of the face, remembering to leave the top of the head free for the cress to grow like hair.
• Place the Mr Cress head on a saucer, water well and leave on a windowsill.
• When the seed germinates, cut a cross shape in the top to allow the cress to grow through the tights.
• When the cress has grown, cut your cress person’s hair and use in a salad or a sandwich – yummy.

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Growing Cress Heads with Children

Cress heads are a very easy activity to do and can be done throughout the year. It's a great way of showing seed to food in a relatively short period of time so that your child can see the whole growing process from start to finish and be involved throughout. Give it a go - kids love it!

Cress is just great if you want to do something with the children where they can see the fruits of their labour early on. I would most likely go so far to say that it is one of the easiest things to grow and what’s more, you can grow this indoors – perfect for getting those green fingers ready for the spring. And it goes lovely in those egg sandwiches that you can have ALL year round!  

Because cress is just so simple to grow, you can use it as a good experiment with the children to show them all the things that plants need to grow. OK – we will be using cotton wool for this one and not nutritious soil that we use for other herbs and vegetables. But cress still needs water, sunlight and warmth to grow.  

How long will it take? About 10 days and it will be ready to eat

What can you do with it? Eat it! And have some fun cutting the hair of course!  

Difficulty Rating: Easy

How to do it

Let’s start by saying that it is not rocket science! But you are going to need some key things to get started:  

What you will need

Eggs – yes, you can eat them first – just be careful how you crack them. Past experience shows that boiled eggs are best

Cotton Wool – A staple in every family home

Cress Seeds – Bought from any garden centre. We use these ones from Amazon

Coloured pens – Some coloured pens to decorate the eggs. You can also use other craft if you want to get creative!  

Something to stand them in – Egg boxes are find for this but you can also make a little person if you are an arty type.  

Preparing the eggs

There is one of two things that you can do here. You can either boil the eggs and eat them – saves on wastage. Or, you can literally put some very small holes in the eggs and drain out all of the insides. Either way, you need to be careful not to crack too much off the top of the egg. About that of the picture below.

Once you have the egg shell with nothing in it, wash them out so that there are no ‘bits’ left that will begin to smell a few days down the line.  Warm water is fine. 

Decorate the eggs

Decorate the eggs. It is best to do this now so that you don’t end up spilling the seeds when you pick them up later.  

Filing the eggs

Now that the eggs are clean, you can start putting the filling in them. We’re going with cotton wool on this one but you can use compost if you wish – it is just a little messier. Put enough cotton will in so that it comes up to about 1cm below the top of the egg

Add the seeds

No sprinkle some seeds on the top of the cotton wool and mist spray with some water. If you don’t have a mister, we found the next best thing to use is a Call syringe (most homes have a few of these lying around).  

It will only take a few days for you to see the results. These seeds germinate pretty quickly.

Whilst the seeds are growing, don’t forget to water them. They don’t need much, only a small amount every couple of days. If you have them in full sun on the windowsill, you might want to water them with only a little every day. If you have a spray gun, this will be fine. However, we actually use the Calpol syringe as we can get to the area where the roots are. This way is also great for little fingers as they can use them pretty easily.

After only 10 days, we have our Cress Heads!!

Time to give them a quick haircut and enjoy some lovely egg and cress sandwiches! For the next round, I think I am going to need to get more creative!!

So there is cress! An easy to grow plant, it tastes delicious in an sandwich with eggs and you can grow it all year round!

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The Imagination Tree

Creative play and learning for kids

Growing Cress Heads and Cress Initials!

January 30, 2012 by Anna Ranson

By day 6 the cress had grown fully and it was time to give it a hair cut! Also a great way to sneak in some scissor skills in a fun and creative way, and something that Cakie is just beginning to show a real interest in too.

The little cress heads looked rather the worse for wear after their “shearing” by the toddler hairdresser, but they still managed to smile!

And we were left with a whole bowl full of cress to eat in our salad!

Learning Links:

• science: investigate how plants grow, grow plants from seed, learn that a plant needs light and water to grow
• maths: talk about growing from small to big, measure growth and height, make comparisons
• phse : take care of another living thing, learn responsibility
• literacy: begin to recognise graphemes and significant letters from own name

January 30, 2012 at 9:19 pm

Oooooh, what a lovely idea! Am definitely pinching this.

January 30, 2012 at 9:22 pm

Lovely! It is quite amazing how much learning can go on with so few ingredients 🙂 I remember my boys loving growing cress too. Thank you for sharing.

January 30, 2012 at 9:42 pm

My daughter would love to do this!

I’d love for you to link up and share: http://tutusandteaparties.blogspot.com/2012/01/pinteresting-party-week-24.html

January 30, 2012 at 10:46 pm

Ahh – Cress-heads! Have you tried sprinkling bread and butter with a little cress? It’s a Milly-Molly-Mandy ‘recipe’ and is the only way my two will even contemplate getting the green stuff near their mouths. Delish!

January 30, 2012 at 11:06 pm

Brilliant idea! xx

January 30, 2012 at 11:17 pm

Has anyone ever seen these in the U.S.? I never have.

January 31, 2012 at 4:50 am

January 31, 2012 at 10:44 am

Another lovely post 🙂 We ran a competition a while back with our kids club to create their own cress heads. It’s so easy, but so much fun to do 🙂

January 31, 2012 at 1:04 pm

This is another great idea. Your ideas are the best because they are simple and doable, but are well carried out from beginning to end and maximize learning effortlessly each step along the way! Thank you!

April 29, 2012 at 2:45 am

cute! Growing plants (especially ones you can eat!) are a great hands-on lesson for kids

http://www.eyeseefaeries.blogspot.com

June 16, 2012 at 10:55 pm

Any idea what this would be called in the U.S.?

July 31, 2012 at 7:37 pm

August 6, 2012 at 5:49 pm

I can’t find the seeds anywhere in the states. Chia seeds are expensive bc apparently they are used as a nutritional supplement. Any other ideas or sources for the seeds. Would love to do this with my kids.

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29 April 2020 Setup time: ~1/2h Run time: 1-2 weeks Age range: 3+

Investigate what seeds and plants need to grow. Introduce the basic idea of a controlled trial.

You will need

• cress seeds 1 1 1 The cress seeds are the one thing you need for this experiment that you're unlikely to already have at home. But you can buy packets of cress seeds on e.g. Amazon for around £5 including delivery. The seeds keep almost indefinitely. So even if they take a while to be delivered by post at the moment, they should work fine in the experiment once they arrive. Alternatively, you could try the experiment with whatever seeds you can get your hands on. Let me know if you find other types that also work well.
• 4 trays (plastic food trays are perfect - remember to wash them throughly first!)
• 2 cardboard boxes (big enough for the trays to fit in)
• 4 pieces of kitchen roll, or enough cotton wool to line each tray

How to do the experiment

Setting up (about 1/2h).

• If the boxes have any holes in them, cover over the holes by sticking pieces of cardboard or paper over them so the boxes are dark inside when closed.
• Cut a large window in the side of one of the boxes. Leave the other box intact.
• Line the bottom of each tray with a piece of kitchen roll folded to fit, or with a layer of cotton wool.
• Sprinkle a similar number of seeds in each tray. It doesn't matter too much if you use a generous number of seeds or a light sprinkling. 2 2 2 More seeds means more cress to eat later! But fewer seeds means you can do the experiment again - I usually manage to get two runs of the whole thing out of one packet of seeds.

Pour water into three of the trays. Don't put any water in the last one.

Use enough water to thoroughly soak the kitchen roll or cotton wool, but not so much that there's a lot of water sloshing around the bottom of the trays. You can always tip out any excess.

Put one of the watered trays inside the box without the window. Put another of the watered tray inside the box with the window. Put both the boxes and the remaining two trays (one watered, one dry) somewhere that gets daylight. 3 3 3 Strictly speaking, for a full controlled trial we ought to have one more: a tray in the dark and without any water. It will do exactly the same as the tray without water in daylight: namely, nothing at all! If you want to be more thoroughly scientific about this, and you have enough seeds and boxes, go ahead and add this extra tray. It doesn't need to be direct sunlight. Near a window is good, but anywhere that gets some natural light shoule be fine.

If you put the trays near a window, or anywhere that gets more light from one side than the other, make sure you rotate the trays that are in the open at least once a day for best results.

Observing (a few minutes each day, for about 1 week)

• Each day, take the trays out of the boxes (remember which tray came from which box), and have a look at what's happening to the cress.
• Prompt your children to observe and describe what they see, especially the differences between the cress in the different trays. Encourage them to think about why the seeds are doing what they've seen, and why the cress in different trays is growing differently. See What to talk about for suggestions.
• Water the same 3 trays as before (the two trays from the boxes, and one of the trays in the open). Don't water the last tray (the second tray in the open).
• Put the trays back into the same boxes they came from, and close the boxes.
• Rotate the trays that are in the open, so they get light from all sides.

After about a week, there should be obvious differences between the cress in the different trays. Once you've finished this part of the experiment, you can eat the cress from the tray that had both water and light if you like!

This experiment reliably gives good results if you remember to water the cress regularly . The only time I've seen it fail was during a summer heat-wave, when the cress wasn't watered enough and died. 4 4 4 Despite this, the cress had grown enough before it died for me to have an insightful half-hour scientific discussion about trays of dead cress, with a group of very interested 3-4 year-olds! Don't worry if things don't work the first time. Working out what went wrong can be more scientifically interesting and teaches at least as much as the experiment working perfectly first time. Experiments not going as planned is part of the scientific discovery process, and one that's very familiar to all scientists. If the weather's hot, make sure you keep the kitchen roll or cotton wool thoroughly soaked. You might need to water it more than once a day if it's very hot.

What to talk about

Prompt your children to observe what's happening to the cress and think about why that might be happening, by asking questions such as:

• Is anything happening to the seeds in this tray? (E.g. the one with water in the open.)
• What about the seeds in that tray? (E.g. the one that without water.)
• Why do you think the seeds in the other trays are growing, but the seeds in that one aren't?
• What's different about the tray where the cress isn't growing?
• Why do you think seeds don't grow when they're in the packet?
• How do they know to start growing?
• What can you see happening in this tray?
• What differences can you see between this tray and that tray? (E.g. the one in the open and the one from the box.)
• What colour is the cress in the tray in the open? What about the one from the box?
• Can you see any other differences between the cress in the open and the cress from the box?
• Which one is taller and which one is shorter?
• Why do you think the seeds in the box did that?
• What do you think the seeds in the open have, that the seeds inside the box don't have?
• Where do you think the seeds in the dark thought they were?
• What do you notice about the cress in the box with the window?
• Why do you think they did that?
• You can extend the experiment by taking the trays out of the boxes and placing them in daylight, and now watering all the trays.
• Each day, have a look at what's happening to the cress now.

After about another week, all the cress should look more like the tray that started out in daylight and with water. (Which you might have eaten already! The rest of the cress should taste nice now, too.)

• What's happening to the cress in each tray now?
• Why do you think it's doing that?

What to expect

After you've set the experiment up, it will take a couple of days for the seeds in the trays being watered to start sprouting:

It will take a few more days before you will start to see differences between the cress in the different trays:

And it will take about a week for the cress to be fully grown, at which point there will be clear differences between the four trays:

After you take all the trays out of the boxes, place them in daylight, and start watering all of them, it will take about another week for all the cress to look more like the tray that started out in daylight and with water:

What's going on

Wet and dry.

Like us, plants need water to survive. Because water is so essential to life, seeds won't even germinate (start to grow) without it; they'd quickly die from lack of water if they did. So seed germination is triggered by water:

The seeds in the tray that doesn't have any water will just sit there, doing nothing. Just like they did in the packet:

When you give them some water in the second half of the experiment, they start to sprout:

Light and dark

Whereas we need to eat food to get energy to survive, plants get their energy from light. Chlorophyll (the green stuff in plants) uses energy from light to turn carbon dioxide from the air and water the plant gets through its roots, into sugar which the plants then use as an energy source: a process is called photosynthesis. The seeds growing in daylight quickly turn green, as they make clorophyll to start using the light energy to make sugar:

The cress inside the completely closed box isn't getting any light, so clorophyll would be no use to it. It's yellowish-white because it hasn't produced any green clorophyll yet:

As well as being yellowish-white instead of green, the cress in the dark grows faster and taller than the cress in the daylight, because it's trying to reach daylight as quickly as possible.

Usually, if seeds find themselves in the dark, it's because they're underground. So the first thing they do is grow as fast as possible upwards, until they reach the surface and daylight and start producing clorophyll.

Light from the side

The cress in the box with the window gets plenty of light through the hole we cut in the side of the box. So it grows and turns green like the cress growing in the open:

But after a few days, the cress in the box with the window will be noticably bent over towards the side of the box with the window, where the light is coming from:

The cress is trying to get as much light as possible, so it can generate plenty of energy by photosynthesis. So it grows towards the light, and bends towards the window. Whereas (if you remember to rotate it regularly!), the cress growing in the open is getting light from all sides, so there's no reason for it to bend one way or the other, and it grows straight:

Thinking like a scientist

Observing, then asking "why".

It doesn't matter whether it's about discovering what seeds need to grow, or about discovering the Higgs boson: science starts with noticing something interesting, then asking "why?" 5 5 5 Which young children often excel at! Learning what plants need to grow is interesting. But learning to carefully observe what's happening, learning to then go onto think about why it happened and try come up with some explanation, is far more important. These are key skills of any scientist. Science isn't a collection of facts; it's a way of asking questions that leads to new facts and new discoveries.

It's more important to encourage your children to look carefully and tell you what they notice about the cress for themselves, than to get them to spot the "right" things. They may need some help and guidance to notice some things. But helping and encouraging them to spot things for themselves, rather than pointing it out to them, encourages an interest in observing things around them.

Young children will likely need a little more help in thinking about why the cress did what it did. But again, encourage them to think about it for themselves, rather than just explaining what's going on. Children are creative, and directing that creativity towards trying to come up with explanations of things they observe, however wrong or fanciful or "non-scientific", is a more significant step towards thinking like a scientst than learning why cress grows faster in the dark.

Controlled trials

If we're trying to work out what things plants need to grow, it's no good just planting seeds, watering them, giving them daylight, and seeing them grow. It could be they need water and light to grow. Or it could be they just need water. Or just light. Or maybe they don't actually need either. If you'd planted them in soil, you might think they needed soil to grow. And how do you know the crucial thing wasn't the water or the daylight, but the fact that you happened to plant them in a blue flowerpot?

To tease apart which factors are important, and what effect each one has, we need to test them one at a time. By comparing the two trays in daylight, one with water and one without, keeping everything else the same, we can see what effect water has on the seeds. By comparing the tray in the closed box (which we watered) with the tray in the daylight which also got water, we can see what effect light has on the seeds, all else being equal. By comparing the tray in the box with a window cut out, with the tray in the open which we rotated regularly to make sure it got light from all sides, we can see whether the direction the light is coming from has any effect.

Wherever possible, scientific experiments need a control group : one (or more) other runs of the same experiment changing just one factor at a time, to see if that particular factor made any difference, and exactly what difference it made.

The idea of a controlled trial may be too complex to explain to young children directly. But seeing it in action is a good way of introducing the idea from early on. Encourage your children to compare two trays of cress at a time, and spot the differences between them. Then get them to remember what you did differently to the two trays when you first set them up, and each day after that. Finally, encourange them to think about what effect that difference might have had, and discuss with them their ideas for why it might have had that effect. This already gets across the idea of comparing one factor at a time (water, light, and light direction in this experiment), and working out what effect each individual factor has, separately from the other factors.

• Add an additional tray in the fridge I sometimes add another tray of cress, with water but putting it in the fridge. Like the tray inside the box, it doesn't get any light. But the cold slows the growth significantly. So, unlike the cress in the box which grows quickly, the cress in the fridge barely grows at all.
• Other types of seeds Cress is a good choice, because it's very easy to grow and makes this experiment very reliable. But it would be interesting to know if it works well with other types of seed, too.
• Other ideas? Let me know!

If you try this experiment with your own children, I'd be very happy to hear feedback on what worked well, what didn't work well, whether it was easy to follow, whether the explanations were clear, or anything else. I will continue to edit and improve this page over time. You can post public feedback on this page using the form below, or send me an email .

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Using Cress in the Lab

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Age Ranges:

Cress seeds are cheap and easy to grow, and offer a useful way to look at the germination process and the many factors that can affect it.  As such, they’re frequently recommended in  biology specifications and used by many schools. White mustard ( Sinapsis alba ) seeds make a useful alternative in these practicals, being frequently cheaper and easier to handle, and slightly more reliable in germination.

• Plant growth: Resource:   Explore whether cress seedlings grow towards light
• Plant growth: Resource:   A simple protocol for investigating seed germination
• DNA: Cress and other brassicas are suitable for the SAPS / NCBE PCR technique, and can be contrasted with spider plants. Resource:  Investigating plant evolution with the SAPS / NCBE PCR kit
• Student project idea:   Do tomato extracts inhibit the germination of cress seeds?
• Student project idea:   Selecting plants for growth studies
• Student project idea:   The effect of heavy metal chlorides on cress seedlings
• Plant growth: Idea: Investigate the effect of water on germinating seedlings (following the protocol above)
• Effects of pollution: Idea: Investigate the germination of seeds and growth of seedlings in different levels of acid rain (following the protocol above)
• Photosynthesis:   Investigating the behaviour of leaf discs

Teaching Topics

• Effects of Pollution
• Plant Growth
• Plant Nutrition

Description

Cress,  Lepidium sativum

Commonly grown in England as a salad crop with mustard ( Sinapsis alba ). The two together will be familiar as the ‘mustard and cress’ found in egg sandwiches. Cress is a member of the Brassicaceae family, as are  radishes  and  beetroot .

Cress is generally quick and reliable to germinate, which makes it a useful choice for experiments looking at the germination process and factors that affect it, such as pollution. However, it is always worth considering the use of white mustard ( Sinapsis alba ) seeds instead, as they are frequently cheaper, are easier to handle, do not have the distinct odour of cress, and their germination has been found to be more reliable in schools.

Note that ‘cress’ sold in a supermarket is not necessarily  Lepidium sativum : it is often another brassica, such as white mustard or oil seed rape. These are still suitable for use in the ‘photosynthesis with leaf discs’ experiment.

Growing and sourcing

Obtaining: All the main seed suppliers stock this plant, as do Blades Biological. Each seed pack contains around 1,000 seeds providing an economical source of quick growing, tiny plants for a wide range of classroom investigations.

Propagating: An excellent, inexpensive plant easily grown from very small, red-brown seeds. Each seed has deep, three-lobed cotyledons and takes between 10-14 days to grow.

Compost: Damp cotton wool or filter paper provides an ideal growing medium as does damp paper towel. You can use petri dishes in a modified plastic bottle.

Light: Keep the seeds dark until after germination and then move to a warm well-lit spot making sure the growing surface stays moist.

Water: Keep damp without soaking.

Temperature: Keep in room temperature.

Feeding: There is no need to feed these seedlings.

Notes: Look out for signs of ‘Damping-off” in your seedlings.

• Agriculture and farming
• Climate change
• Genetics and evolution
• Inheritance
• Photosynthesis
• Plant growth
• Plant nutrition
• Plant reproduction
• Plants in the Science Curriculum

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Teaching resources.

• Student Sheet 5 - Investigating Seed Germination
• Using Mung Beans in the Lab
• Using Radishes in the Lab
• Using Beetroot in the Lab

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Home » Year 3 – Class 4 – Making observations and drawing conclusions from our cress experiment!

Year 3 – Class 4 – Making observations and drawing conclusions from our cress experiment!

Class 4 spent some time this afternoon observing and comparing the similarities and differences between the different pots of cress that we have been growing in different conditions. We have been investigating how plants grow when deprived of light, water, nutrients, space or warmth.

Tinshill Drive Cookridge Leeds West Yorkshire LS16 7DH

0113 386 2500

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Plants Fair Testing Investigation using cress

Subject: Primary science

Age range: 5-7

Resource type: Lesson (complete)

Last updated

28 May 2024

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